This wonderful clip shows Reactable - a research project from Universitat Pompeu Fabra in Barcelona. It's a translucent table with a camera and a projector underneath. The camera scans the positions of various blocks, which can be twisted and linked. We've seen this kind of stuff before - Audiopad seems the most similar, and multitouch might be more practical - but I'd love to play with this thing myself... (thanks, Bram)

The design of the hardware is incredible. The sounds - as implemented - are unbearable. There clearly needs to be more than one oscillator and some part of the interface needs to specify pitches. Maybe an "easy mode" which can only produce the 12-tone scale, and an "advanced mode" which can produce any pitch.